Also do not need XHTML-style self-closing tags

Author: jglick

pom.xml

@@ -29,7 +29,7 @@
         <groupId>org.jenkins-ci.plugins</groupId>
         <artifactId>plugin</artifactId>
         <version>4.40</version>
-        <relativePath />
+        <relativePath/>
     </parent>
     <groupId>io.jenkins.plugins</groupId>
     <artifactId>pipeline-groovy-lib</artifactId>